1. Field
Example embodiments relate to X-ray detectors including diffusion barrier films to suppress and/or prevent a reaction between a photoconductor and a pixel electrode.
2. Description of the Related Art
X-ray detectors including thin film transistors (TFTs) are used for medical diagnosis. Conventional X-ray detectors output a digital signal in the form of an X-ray image or an X-ray fluoroscopy image. Such X-ray detectors operate via a direct method or an indirect method.
A conventional direct method X-ray detector includes a photoconductor that generates electron-hole pairs in response to irradiated X-radiation, and pixel electrodes that receive electric charges from the photoconductor. The X-radiation is directly converted into electric charges by the photoconductor.
A conventional indirect method X-ray detector converts X-radiation into a visible ray using a scintillator, and converts the visible ray into electric charges using a photoelectric transformation element such as a photodiode.
Mercury(II) iodide (HgI2) is a material used to form the above-mentioned photoconductor. Because HgI2 has a relatively high atomic weight, HgI2 having a relatively low thickness absorbs X-radiation relatively easily. HgI2 also has a relatively low ionization energy in response to X-radiation, and thus, HgI2 has been considered as an appropriate material for the photoconductor. However, HgI2 has a relatively high reactivity with most metals, and thus, corrodes most metals.
If pixel electrodes are formed of a metal with a relatively low resistance, the Hg of HgI2 diffuses into the photoconductor over time because of the relatively high reactivity between Hg and the metal. This results in deterioration and/or degradation of photoconductor properties.